A Lull in the End
by rrllao
Summary: The end of the world that the sea god predicted came sooner than expected, in fire and blood instead of ice / collection of stand-alone pieces for a NagiAsu x OwaSera fusion series.
1. Chapter 1

**fandom** : Nagi no Asukara x Owari no Seraph crossover  
 **pairing(s)** : Chisaki Hiradaira/Tsumugu Kihara  
 **warning(s)** : references to minor canon character death  
 **notes** : Contains minor original characters who are there for background purposes. This focuses on NagiAsu characters more than OnS ones and so will the rest of the series. All canon NagiAsu characters mentioned in this are at least 17 years old. Each chapter is stand-alone unless marked otherwise.  
 **chapter summary** : Chisaki has an encounter with a vampire while on an item retrieval mission with her squad.

* * *

"Chii! Behind!"

Manaka's warning shriek is perfectly timed- Chisaki lifts her naginata up and over her back to meet the descending blade behind her, twists away from the sparks created by the slide of metal against metal. She turns around quickly and brings the shaft back up to defend as the vampire pushes forward in attack.

Deep early morning fog surrounds the docks where Chisaki's squad has been working on opening rusted shipping crates and checking for usable supplies in the boats that haven't drifted loose from their moorings. Chisaki had briefly gotten lost due to the fog, ending in her coming back late from her perimeter patrol. She'd immediately been on her guard after hearing Natalie's piercing whistle of warning; now she's fighting her way back to the trucks, but the fog combined with the darkness of the hour is making things difficult. Her vision is more obscured than she'd like it to be and she doesn't have the luxury of overhead light from the long broken streetlights. She can't wield her cursed gear effectively at close range, but she can't break free for long enough to gain ground, either. She thinks about calling for backup, but a gust of ocean breeze clears her vision for long enough to see that it would be pointless.

The rest of her squad is busy with their own problems- Isuzu's been cornered waist-deep in the water by a vampire and is barely defending herself, Natalie and Manaka are keeping an eye on the cargo they've already salvaged while Hikari and Yuri pick off the remaining vampires surrounding them. Whoever it is that Chisaki is fighting, they're stronger than the vampires attacking her squad members and Chisaki curses her luck.

"Chii!" Manaka calls again as another swirl of dense fog obscures the smaller girl's field of vision.

"Manaka! I'm fine," Chisaki calls back. The vampire in front of her hesitates.

"Manaka? Then, are you really…?"

Their voice is low and somewhat familiar- Chisaki's heart starts to beat faster and she leaps backward, raises her weapon and finally begins to push back. They clash back and forth through the shipping yard. Chisaki chases after them even when Natalie whistles an all clear signal, determined to bring her opponent's face to light. There was something familiar about how they'd said Manaka's name, and she wants an answer to her unspoken question.

Chisaki ducks into a row of shipping containers even though it limits her ability to swing, defending with the shaft of her naginata until she's cornered at the end of the row. Her chest is tight with anticipation and her body thrums with adrenaline- this vampire could easily overpower her, and yet they haven't. Chisaki licks salt from her lips and looks up at where her opponent stands, sword lowered by their side. She's only a few feet away from them, breathing hard from the exercise and shivering in the cold ocean breeze. The fog is starting to disperse now that the sun is rising, and the vampire straightens, steps to the side into a patch of weak sunlight, and Chisaki's breath catches in her throat. Dark brown hair, slicked back and damp with salt water, brown eyes and-

"Chisaki?"

"...Tsumugu?"

Chisaki's pulse is racing. It's been so long since she last saw her old junior high classmate- has it been six years, or seven? Everything after the calamity is blurred in her memories, a haze of saltwater and blood.

The last time she can remember seeing Tsumugu was in their homeroom class a few hours after the sudden and violent deaths of all adults on campus, during what she knew now was the beginning of the end. Hikari and Kaname had gone through the school and gathered all their remaining classmates, plus as many other students who hadn't gone home yet as they could find. They had gathered in the one classroom that didn't have a dead adult in it, trying to make sense of what had happened and attempting to calm some of the more hysterical students. A student from the high school- one of the younger ones, a pale girl with bloodstains on her blazer who clutched a cellphone with a broken screen to her chest- had just informed them of the strange people in trucks who were making their way through Oshiooshi and rounding up stray kids, and who were now heading towards the school. In the immediate ensuing panic, Hikari had barely been able to pull Tsumugu aside to inform him that the Shioshishio kids were going back to their homes. Sayu and Miuna, both of whom had been brought back to the junior high by an older student, had started crying again after Hikari had pried Manaka away from them.

Chisaki remembers how cold she felt the whole time, like she was floating away into the sky, and how Tsumugu had looked at her before they left, had held her hand for a moment and murmured "I'll see you again, I promise," in her ear before pushing her out of the classroom. Hikari and Kaname had had to pull Manaka up onto her feet because the smaller girl was still in shock, and then they were rushing up the hill behind the school and down through the forest path towards the sea.

Her heart is hammering in her chest, hard enough to make her throat hurt, making it hard to breathe. Chisaki can only gulp nervously when Tsumugu steps forwards into her space, looking everywhere but his face- at the bloody red spikes receding from where they'd punched through his fist, at the stark white of the Sanguinem uniform and the flex of his boots against his thighs. Chisaki is startled when Tsumugu lifts his free hand and reaches out to touch her cheek.

"You've changed," he says quietly, looking her up and down. She flushes and readjusts her grip on her naginata. Even with the food shortages she and the other Shioshishio kids had suffered, Chisaki had emerged from puberty as a beautiful young woman, soft and curvy and someone that made heads turn when she entered a room. Discomfort curls in her chest at Tsumugu's statement.

"I could say the same," she replies just as quietly. There's an edge to her reply though, one born from the fact that she is wearing JIDA blacks and he is wearing Sanguinem whites. Chisaki wonders what must have happened in that underground city to change her old classmate into this, a young man who is stronger than the vampires she fights on a regular basis but whose eyes are still the same calm, soft, human brown they've always been.

Tsumugu brushes a lock of hair back from her face. The look on his face is strangely fond; Chisaki can feel herself blushing at having been caught staring.

It's been years, and still the words from that day echo in her head. They'd been a promise that had carried her through the horror of what had been waiting for her and her friends back in Shioshishio, through the years spent underwater without so much as the feel of sunlight on their bare skin, and had been her anchor when she'd finally surfaced and gotten recruited into the JIDA. The feelings she'd harbored for Hikari back then had faded the more time passed, lost in the constant struggle to survive and take care of each other and the two other kids from Shioshishio who had been left without parents or other relatives. On bad nights when she couldn't sleep due to nightmares, or when she woke early before everyone else, she'd repeat those words to herself out loud until she felt calm again. She clung to the memory of Tsumugu's hand holding hers and how he'd promised to see her again.

Tsumugu's still standing close to her, watching her intently. Chisaki's not sure when she started trembling but she is- she might even be crying a little, but her face is already wet from ocean spray so she can't really tell. There's so much she wants to say to him but all the words are stuck in her throat. The pounding surf behind them echoes the beat of her heart. Chisaki's lips are starting to chap but she licks them again anyways, conscious now of how Tsumugu stares at her mouth and throat.

He starts to say something and takes her free hand in his, leans in close. She only has to tilt her head up a bit and their lips brush once, then again in a kiss that feels like the inevitable conclusion to those words she heard so long ago.

"Chisaki! Heeey! Where are you?!"

Hikari's shouting breaks the atmosphere around them and Chisaki jumps back, bringing her naginata up defensively. Tsumugu looks back up towards the street too, cocks his head to the side like he's listening for something she can't hear.

"I have to go," she hears herself saying. "Tsumugu, will you- will you be okay?"

"Yes," is all he says as he leads her out of the maze of shipping containers. "I have been so far. Now I know I will continue to be."

"Hiradaira! We're leaving! Where did you go?" It's Isuzu's voice this time and she sounds closer than Hikari. Chisaki is reluctant to leave Tsumugu, but she knows how badly her squad members will react if they see him.

"I'm on my way back!" she calls, and Tsumugu squeezes her hand. She turns to him for a quick kiss before letting him go. He pushes her towards the trucks that have appeared by the shipping yard's front gate. "I'll see you again," she says when she's halfway to the trucks. She didn't look back, and Tsumugu is gone from her sight anyways, but she knows he can hear her. "I promise." She presses the hand he'd held close to her heart.

Manaka runs up to her from behind one of the trucks, her signature feather earclips bobbing up and down.

"Chii!" she cries, "I was so worried! The fog rolled out and I couldn't see you and then you didn't come back when Miss Natalie gave the all clear-!"

"Sorry for worrying you," Chisaki replies, giving her friend a one-armed hug. "I, uh, I got lost in the shipping containers."

"Hiradaira, Mukaido," Isuzu barks from where she's now sitting in the driver's seat of one of the full trucks. "You can chat later, let's get going before they come back."

"Did we get everything Kaya asked for?" Chisaki asks absently as she helps Manaka climb into the back of a second truck and follows after her. Manaka nods excitedly and begins to chatter at her friend, post-battle stress evident in how tightly she's gripping her crossbow to try and hide the way her hands are shaking. Chisaki is only half-listening, lost in thought as Hikari slides into the driver's seat of their truck and starts it. He follows Isuzu out of the shipping yard and back onto the road towards their unit's headquarters. Manaka goes quiet after a while and leans against the taller girl, playing with one of her feather clips absentmindedly.

"Hey, Chisaki," she asks suddenly, "What happened to your glove?" She touches Chisaki's hand, the one Tsumugu had held. It's bare, unlike the hand gripping the shaft of her naginata.

"I don't know," is the only reply she can think of. "I guess it came off when I wasn't paying attention."

That's a lie: Tsumugu had slipped the glove off her hand when she let go of him and he'd pushed her towards the gate, she'd felt the soft fabric against her skin and the sudden cold air on her palm. He slipped the plain black glove into a pocket somewhere, given her one last half smile before turning to run in the opposite direction of the trucks.

Chisaki flexes her fingers and finally relinquishes her hold on her weapon, carefully stowing the blade away in the sheath at her waist and lowering the shaft to the floor between the seats. Hikari is watching her from the rearview mirror and once she catches his eye he looks back out at the road instead. She gets the feeling that he knows she lied, and wonders if he was close enough to see Tsumugu when he left. For now, she'll hold this secret close- meeting Tsumugu again- until she can feel out how her friends will respond to the news. She wonders if they will even remember him.


	2. Chapter 2

**pairing(s)** : mentions of Chisaki/Tsumugu  
 **warnings** : mentions of canonical violence from vampires against humans, referenced off-screen deaths, mentions of minor character death.  
 **notes** : Continued from the first chapter, this is part 2 of 2. This part contains an original character! Also included in this chapter is some more worldbuilding, explanations of what happened to Tsumugu, Sayu and Miuna, etc. I didn't do a good job of transitioning scenes like I did in ch1 so I've added some scene breaks. Hopefully they don't get removed from my formatting.

 **chapter summary** : Tsumugu returns to Sanguinem after his encounter with Chisaki and reminisces about the past, sort of.

* * *

Tsumugu sighs with relief when he's finally allowed to leave Janus's side; he only barely manages to walk calmly back to the private quarters he's been assigned to. In the vague privacy of his room he starts to shake, grips his cloak tight in clenched fists.

"Chisaki," he says out loud. "And Manaka, and Hikari…" They're alright. They're alive. They survived. He's already thinking about how he can find a way to meet Chisaki again, to talk to her properly and find out how she and the other Shioshishio kids survived this long. How they ended up in the JIDA, of all places.

Not for the first time Tsumugu experiences a slight pang of regret over giving up his humanity so fast when Janus had first asked him if he'd like the change. It had been necessary in order to become stronger, so he could keep Sayu and Miuna safe from the worst of the blood halls and the coarser vampires who fed there. He had thought that, eventually, he'd be able to go back to Oshiooshi and from there search for a way to reach the village under the sea. He hadn't expected to meet his old junior high classmate again in a town he didn't remember the name of, much less for her to be wearing the uniform of the Japanese Imperial Demon Army and wielding cursed gear against him.

He runs over their encounter again in his head.

Chisaki was strong, able to keep pace with him while he'd fought her in the fog. She had kept her weapon between them even when he had her cornered by the shipping containers and had only let her guard down after he did so first. Seeing her for the first time in so many years has uncovered the emotions he'd made an effort to tamp down back when they were first separated.

Chisaki is a beautiful woman now, with her long indigo hair still tied up the same way and soft bangs framing her face. She's grown into the childish roundness of her cheeks and chin, stands straight and tall for all she's a good half foot shorter than him. Tsumugu knows she probably misunderstood what he meant when he said she's changed- that's another thing they'll have to talk about when they meet next. Speaking of meeting, Tsumugu remembers guiltily, he needs to go see Sayu and Miuna before he can rest for real.

The two Oshiooshi girls have clung to him like shadows ever since they had first been carted off to Sanguinem, with Miuna still covered in Akari's blood and Sayu gripping her friend's hand so tight she'd left nail marks. They'd been separated for a bit during the vaccination process- boys and girls separated, then further separated into landfolk and seafolk to receive the correct vaccine. After that, they'd been reunited and assigned the same house, together with other kids Tsumugu remembered from school, plus a few he didn't recognize.

The entire situation was a giant nightmare that Tsumugu didn't think he'd ever wake up from. The blood halls in particular were a source of distress for most of the younger kids, Miuna especially. He wasn't the only older kid who'd had to step in when a vampire tried to sneak or threaten their way into getting a bite from the source, and he'd earned a good number of minor injuries because of it.

The arrival of America's twentieth progenitor, Janus Guidix, as a guest of the vampire queen Krul Tepes, in the third year after the calamity had set the entire vampire community on edge. Tsumugu, like most of the other kids, knew little about vampire politics, but some of the older girls who cleaned in the mansions whispered about Janus coming to Japan in order to show her support for Krul in whatever the queen was currently getting up to. It didn't involve him, so he didn't think too much about it. At least, not until he met the visitor herself.

He had gotten involved in an altercation between a vampire and one of the younger children in the blood hall, adamantly standing his ground because the child in question was already pale from having given blood and also crying with fear. It had almost gotten too violent for Tsumugu to handle, until Janus passed by.

The vampire noble had calmly speared the offender through the heart with a swipe of her hand before turning to Tsumugu and asking him if he'd like to dine with her in the same breath. He didn't think twice before accepting- Tsumugu knew from talking with some of the other kids that 'dining' with a noble could mean better food for him and the kids in his household, or even better living quarters. If it meant he'd be able to keep Sayu and Miuna and the other kids who were unofficially under his care fed and safe, he'd take the risk.

Tsumugu reaches the house where Sayu and Miuna are living with a few other girls and knocks in the special pattern they'd established as the latest password. Someone runs to the door and opens it cautiously.

"Kihara?" It's one of the other girls, one who's about his age, named Ayu. "Hold on," she says, not inviting him in. "Sayu, Miuna! Come downstairs, you have a guest!" Sayu's the first one down, throws herself at him for a hug. Miuna follows a bit behind her friend but joins the hug as well.

"Welcome back, Tsumugu!" Sayu says eagerly. Miuna nods her agreement- she hasn't spoken since the day Hikari pushed her away from him and left her in Tsumugu's care. The black-haired girl leads them both into the house despite Ayu's scowl, into the kitchen where they can talk and the other girls who are home can keep an eye on Tsumugu. Even though he's responsible for the better food they eat, the others don't really trust him. It's fine by him.

Sayu asks questions about where he's been, what he's seen. She's itching to see the sky again and always has him describe it to her whenever he returns from a mission. Tsumugu hesitates before answering her this time, because he hadn't thought to look at the sky at all when Chisaki had been right in front of him.

He recounts his recent patrol, and when he reaches the part where he met Chisaki, Sayu is the only one who reacts with emotion.

"So they're okay? They're alive?!" she asks, grabbing at his arm. Her eyes shine bright with tears. "Did you see Kaname? Is he alive, too?"

"I don't know," Tsumugu admits. "We...didn't have a lot of time to talk, and I only heard Hikari and Manaka's voices." Sayu bites her lip and wipes at her eyes as her tears spill over.

"That's not fair," she cries, "it's not- why isn't-"

Miuna squeezes Sayu's shoulder and wraps her arms around her friend. She's scowling the way she does whenever she hears Hikari's name, brows furrowed and nose scrunched. She pets Sayu's hair until the other girl stops crying.

Tsumugu ends the visit shortly after that, only letting Miuna tap out the next password sequence on his palm before giving the two girls a careful embrace at the doorway. Ayu watches them from her seat near the windowsill and slams the door behind Tsumugu the instant he steps out.

Tsumugu rubs a hand over his face when he makes it back to his quarters in Janus's mansion. There's only so long he can be around Sayu and Miuna's house before the sound of their heartbeats gets to be too much for him to handle. He's still not used to how strange the need for blood makes him feel- in books, it's been described as a hunger, or as a thirst, but he's not sure he would describe it like that. It's just- a deep feeling, one that's sharp around the edges and very hot. He can usually ignore it but around humans it gets worse, and only Janus's blood can dull this feeling.

The vial of blood is one of his last. Tsumugu drinks it quickly, making sure that every last drop is emptied from the vial before stowing it back in the pouch strapped to his thigh. One vial generally lasts him two weeks if he doesn't need to do any heavy fighting, and with six vials in his possession, he only needs to visit Janus for new blood every few months. He makes a mental note to ask the vampire noble for some of her time tomorrow when he visits for the next mission's briefing.


End file.
